17-4PH Precipitation-Hardening Stainless Steel
AISI 630 / UNS S17400 — precipitation-hardening martensitic stainless, 1,300 MPa UTS. Compare with 440C for high-strength structural blades.
17-4 PH (UNS S17400, AISI 630, DIN 1.4542) is a precipitation-hardening martensitic stainless steel combining high strength (1,300 MPa UTS achievable) with good corrosion resistance. It is specified for high-strength structural blades and die-casting dies where standard 400-series stainless cannot deliver the load-bearing capacity.
Standard composition: C ≤ 0.07 %, Cr 15.0–17.5 %, Ni 3.0–5.0 %, Cu 3.0–5.0 %, Nb 0.15–0.45 %, Mn ≤ 1.00 %, Si ≤ 1.00 %, balance Fe
Hardness: Solution annealed HB 320; aged to HRC 40–44 (H900), 36–40 (H1025), 28–32 (H1150)
Heat treatment: Solution anneal 1,040 °C, age at 480–620 °C for 1–4 h depending on target hardness
Properties: A precipitation-hardening stainless. Achieves high strength (1,300 MPa UTS) and good corrosion resistance. The “H900” condition gives the highest hardness; “H1150” gives the best toughness. Used for high-strength structural blades and dies.
Applications: Aerospace structural blades, die-casting dies, plastic-injection moulds, food-processing parts requiring high strength + corrosion resistance.
Cross-reference: ≈ DIN 1.4542, GB 05Cr17Ni4Cu4Nb, AISI 630.
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